If you try to say things with a knife, the police will put you in a net as your penalty for breaking the knife laws. You can't just go up to other people and say things with a knife out.
Your penalty for breaking the law isn't over. Now that you're stuck in a net, you can't fight back when they hit you with bats (ばつ).
Currently there are no similar looking kanji which exist in the WaniKani learning system